Understanding how the environment contributes to health is a complex challenge, given the vast array of exposures, their timing, and the ways they interact with individual biology and social context. Two notable theories showcase this complexity and require consideration when studying environment’s effect across the lifespan. The differential susceptibility theory highlights interindividual differences in sensitivity to environmental influences. These differences, rooted in each person’s unique biological or psychological makeup, can result in greater responsiveness to both positive and negative environmental factors [11]. In this context, using data-driven approaches to study exposomic effects on health is essential, as it enables the identification of not only risk factors but also protective environmental influences that support resilient mental health trajectories. This is especially important because traditional biomedical research often emphasizes risk exposures, potentially overlooking environmental factors that promote resilience. The sensitive period theory emphasizes that the timing of exposure is crucial, with certain developmental windows making individuals especially vulnerable to environmental influences [12]. Below we highlight key considerations for environment’s contributions to mental health in different epochs throughout the lifespan:
Peri-natal and early childhood
Considered sensitive periods owing to the robust brain development early in life, there is strong evidence that peri-natal exposures, such as maternal stress, nutrition, and environmental toxins, can have profound and lasting impacts on neurodevelopment and subsequent mental health outcomes [13]. Additionally, studies indicate that childhood exposure to environmental chemicals, including heavy metals, endocrine disruptors, and pesticides, is associated with an increased risk of mental health problems in children [14].
Adolescence
This is another window of heightened plasticity due to the brain’s maturation processes alongside transition to puberty. During adolescence, peer influences, school environment, and digital exposures become especially prominent aspects of the exposome. Evidence suggests that social stress and substance use during this period may influence long-term emotional regulation and mental health trajectories [15].
Adulthood
Here individual agency grows, and the exposome is increasingly shaped by occupational and lifestyle choices. Chronic exposures, such as persistent work stress, urban pollution, or unhealthy habits, can accumulate, contributing to allostatic load and increased risk for physical and mental health outcomes including mood, anxiety, and psychotic disorders [16].
Older age
In later life, factors like loneliness, social isolation, and the quality of social connections become central to the exposome’s impact on mental health, with robust links to depression, cognitive decline, and dementia risk [17]. With aging, physical morbidity becomes more salient and reciprocates with mental health, further complicating contributions of exposome to mental health through its well-established effects on age-related diseases [18].
Table 1 summarizes recent works that apply data-driven exposomic approaches, such as exposome-wide-association-studies, to model environment’s contribution to mental health outcomes across the lifespan.
Table 1 Exposomic research related to mental health across the lifespan.